Did you know that the Universe we observe has quite certain boundaries? We are used to associating the Universe with something infinite and incomprehensible. However, modern science, when asked about the “infinity” of the Universe, offers a completely different answer to such an “obvious” question.

According to modern concepts, the size of the observable Universe is approximately 45.7 billion light years (or 14.6 gigaparsecs). But what do these numbers mean?

The first question that comes to mind to an ordinary person- How can the Universe not be infinite? It would seem that it is indisputable that the container of all that exists around us should have no boundaries. If these boundaries exist, what exactly are they?

Let's say some astronaut reaches the boundaries of the Universe. What will he see in front of him? A solid wall? Fire barrier? And what is behind it - emptiness? Another Universe? But can emptiness or another Universe mean that we are on the border of the universe? After all, this does not mean that there is “nothing” there. Emptiness and another Universe are also “something”. But the Universe is something that contains absolutely everything “something”.

We arrive at an absolute contradiction. It turns out that the boundary of the Universe must hide from us something that should not exist. Or the boundary of the Universe should fence off “everything” from “something”, but this “something” should also be part of “everything”. In general, complete absurdity. Then how can scientists declare the limiting size, mass and even age of our Universe? These values, although unimaginably large, are still finite. Does science argue with the obvious? To understand this, let's first trace how people came to our modern understanding of the Universe.

Expanding the boundaries

Since time immemorial, people have been interested in what the world around them is like. There is no need to give examples of the three pillars and other attempts of the ancients to explain the universe. As a rule, in the end it all came down to the fact that the basis of all things is the earth's surface. Even in the times of antiquity and the Middle Ages, when astronomers had extensive knowledge of the laws of planetary motion along the “stationary” celestial sphere, The Earth remained the center of the Universe.

Naturally, back in Ancient Greece There were those who believed that the Earth revolves around the Sun. There were those who spoke about the many worlds and the infinity of the Universe. But constructive justifications for these theories arose only at the turn of the scientific revolution.

In the 16th century, Polish astronomer Nicolaus Copernicus made the first major breakthrough in knowledge of the Universe. He firmly proved that the Earth is only one of the planets revolving around the Sun. Such a system greatly simplified the explanation of such a complex and intricate movement of planets in the celestial sphere. In the case of a stationary Earth, astronomers had to come up with all sorts of clever theories to explain this behavior of the planets. On the other hand, if the Earth is accepted as moving, then an explanation for such intricate movements comes naturally. Thus, a new paradigm called “heliocentrism” took hold in astronomy.

Many Suns

However, even after this, astronomers continued to limit the Universe to the “sphere of fixed stars.” Until the 19th century, they were unable to estimate the distance to the stars. For several centuries, astronomers have tried to no avail to detect deviations in the position of stars relative to the Earth’s orbital movement (annual parallaxes). The instruments of those times did not allow such precise measurements.

Finally, in 1837, the Russian-German astronomer Vasily Struve measured parallax. This marked a new step in understanding the scale of space. Now scientists could safely say that the stars are distant similarities to the Sun. And our luminary is no longer the center of everything, but an equal “resident” of an endless star cluster.

Astronomers have come even closer to understanding the scale of the Universe, because the distances to the stars turned out to be truly monstrous. Even the size of the planets’ orbits seemed insignificant in comparison. Next it was necessary to understand how the stars are concentrated in .

Many Milky Ways

The famous philosopher Immanuel Kant anticipated the foundations of the modern understanding of the large-scale structure of the Universe back in 1755. He hypothesized that the Milky Way is a huge rotating star cluster. In turn, many of the observed nebulae are also more distant “milky ways” - galaxies. Despite this, until the 20th century, astronomers believed that all nebulae are sources of star formation and are part of the Milky Way.

The situation changed when astronomers learned to measure distances between galaxies using . The absolute luminosity of stars of this type strictly depends on the period of their variability. By comparing their absolute luminosity with the visible one, it is possible to determine the distance to them with high accuracy. This method was developed in the early 20th century by Einar Hertzschrung and Harlow Scelpi. Thanks to him, the Soviet astronomer Ernst Epic in 1922 determined the distance to Andromeda, which turned out to be an order of magnitude larger than the size of the Milky Way.

Edwin Hubble continued Epic's initiative. By measuring the brightness of Cepheids in other galaxies, he measured their distance and compared it with the redshift in their spectra. So in 1929 he developed his famous law. His work definitively disproved the established view that the Milky Way is the edge of the Universe. Now it was one of many galaxies that had once been considered part of it. Kant's hypothesis was confirmed almost two centuries after its development.

Subsequently, the connection between the distance of a galaxy from an observer and the speed of its removal from him, discovered by Hubble, made it possible to draw a complete picture of the large-scale structure of the Universe. It turned out that the galaxies were only an insignificant part of it. They connected into clusters, clusters into superclusters. In turn, superclusters form the largest known structures in the Universe - filaments and walls. These structures, adjacent to huge supervoids (), constitute a large-scale structure known in this moment, Universe.

Apparent infinity

It follows from the above that in just a few centuries, science has gradually fluttered from geocentrism to a modern understanding of the Universe. However, this does not answer why we limit the Universe today. After all, until now we were talking only about the scale of space, and not about its very nature.

The first person who decided to prove the infinity of the Universe was Isaac Newton. Discovering the law universal gravity, he believed that if space were finite, all her bodies would sooner or later merge into a single whole. Before him, if anyone expressed the idea of ​​​​the infinity of the Universe, it was exclusively in a philosophical vein. Without any scientific basis. An example of this is Giordano Bruno. By the way, like Kant, he was many centuries ahead of science. He was the first to declare that stars are distant suns, and planets also revolve around them.

It would seem that the very fact of infinity is quite justified and obvious, but the turning points of science of the 20th century shook this “truth”.

Stationary Universe

The first significant step towards developing a modern model of the Universe was taken by Albert Einstein. The famous physicist introduced his model of a stationary Universe in 1917. This model was based on general theory relativity, which he had developed a year earlier. According to his model, the Universe is infinite in time and finite in space. But, as noted earlier, according to Newton, a Universe with a finite size must collapse. To do this, Einstein introduced a cosmological constant, which compensated for the gravitational attraction of distant objects.

No matter how paradoxical it may sound, Einstein did not limit the very finitude of the Universe. In his opinion, the Universe is a closed shell of a hypersphere. An analogy is the surface of an ordinary three-dimensional sphere, for example, a globe or the Earth. No matter how much a traveler travels across the Earth, he will never reach its edge. However, this does not mean that the Earth is infinite. The traveler will simply return to the place from which he began his journey.

On the surface of the hypersphere

In the same way, a space wanderer, traversing Einstein’s Universe on a starship, can return back to Earth. Only this time the wanderer will move not along the two-dimensional surface of a sphere, but along the three-dimensional surface of a hypersphere. This means that the Universe has a finite volume, and therefore a finite number of stars and mass. However, the Universe has neither boundaries nor any center.

Einstein came to these conclusions by connecting space, time and gravity in his famous theory. Before him, these concepts were considered separate, which is why the space of the Universe was purely Euclidean. Einstein proved that gravity itself is a curvature of space-time. This radically changed early ideas about the nature of the Universe, based on classical Newtonian mechanics and Euclidean geometry.

Expanding Universe

Even the discoverer of the “new Universe” himself was not a stranger to delusions. Although Einstein limited the Universe in space, he continued to consider it static. According to his model, the Universe was and remains eternal, and its size always remains the same. In 1922, Soviet physicist Alexander Friedman significantly expanded this model. According to his calculations, the Universe is not static at all. It can expand or contract over time. It is noteworthy that Friedman came to such a model based on the same theory of relativity. He managed to apply this theory more correctly, bypassing the cosmological constant.

Albert Einstein did not immediately accept this “amendment.” This new model came to the aid of the previously mentioned Hubble discovery. The recession of galaxies indisputably proved the fact of the expansion of the Universe. So Einstein had to admit his mistake. Now the Universe had a certain age, depending on the Hubble constant, characterizing the rate of its expansion.

Further development of cosmology

As scientists tried to solve this question, many other important components of the Universe were discovered and various models of it were developed. So in 1948, George Gamow introduced the “hot Universe” hypothesis, which would later turn into the Big Bang theory. The discovery in 1965 confirmed his suspicions. Now astronomers could observe the light that came from the moment when the Universe became transparent.

Dark matter, predicted in 1932 by Fritz Zwicky, was confirmed in 1975. Dark matter actually explains the very existence of galaxies, galaxy clusters and the Universal structure itself as a whole. This is how scientists found out that most of the mass of the Universe is completely invisible.

Finally, in 1998, during a study of the distance to, it was discovered that the Universe is expanding at an accelerating rate. This next turning point in science gave rise to modern understanding about the nature of the Universe. The cosmological coefficient, introduced by Einstein and refuted by Friedman, again found its place in the model of the Universe. The presence of a cosmological coefficient (cosmological constant) explains its accelerated expansion. To explain the presence of the cosmological constant, the concept was introduced - a hypothetical field containing most of the mass of the Universe.

Modern understanding of the size of the observable Universe

The modern model of the Universe is also called the ΛCDM model. The letter "Λ" means the presence of a cosmological constant, which explains the accelerated expansion of the Universe. "CDM" means that the Universe is filled with cold dark matter. Recent studies indicate that the Hubble constant is about 71 (km/s)/Mpc, which corresponds to the age of the Universe 13.75 billion years. Knowing the age of the Universe, we can estimate the size of its observable region.

According to the theory of relativity, information about any object cannot reach an observer at a speed greater than the speed of light (299,792,458 m/s). It turns out that the observer sees not just an object, but its past. The farther an object is from him, the more distant the past he looks. For example, looking at the Moon, we see as it was a little more than a second ago, the Sun - more than eight minutes ago, the nearest stars - years, galaxies - millions of years ago, etc. In Einstein's stationary model, the Universe has no age limit, which means its observable region is also not limited by anything. The observer, armed with increasingly sophisticated astronomical instruments, will observe increasingly distant and ancient objects.

We have a different picture with the modern model of the Universe. According to it, the Universe has an age, and therefore a limit of observation. That is, since the birth of the Universe, no photon could have traveled a distance greater than 13.75 billion light years. It turns out that we can say that the observable Universe is limited from the observer to a spherical region with a radius of 13.75 billion light years. However, this is not quite true. We should not forget about the expansion of the space of the Universe. By the time the photon reaches the observer, the object that emitted it will be already 45.7 billion light years away from us. years. This size is the horizon of particles, it is the boundary of the observable Universe.

Over the horizon

So, the size of the observable Universe is divided into two types. Apparent size, also called the Hubble radius (13.75 billion light years). And the real size, called the particle horizon (45.7 billion light years). The important thing is that both of these horizons do not at all characterize the real size of the Universe. Firstly, they depend on the position of the observer in space. Secondly, they change over time. In the case of the ΛCDM model, the particle horizon expands at a speed greater than the Hubble horizon. Modern science does not answer the question of whether this trend will change in the future. But if we assume that the Universe continues to expand with acceleration, then all those objects that we see now will sooner or later disappear from our “field of vision”.

Currently, the most distant light observed by astronomers is the cosmic microwave background radiation. Peering into it, scientists see the Universe as it was 380 thousand years after the Big Bang. At this moment, the Universe cooled down enough that it was able to emit free photons, which are detected today with the help of radio telescopes. At that time, there were no stars or galaxies in the Universe, but only a continuous cloud of hydrogen, helium and an insignificant amount of other elements. From the inhomogeneities observed in this cloud, galaxy clusters will subsequently form. It turns out that precisely those objects that will be formed from inhomogeneities in the cosmic microwave background radiation are located closest to the particle horizon.

True Boundaries

Whether the Universe has true, unobservable boundaries is still a matter of pseudoscientific speculation. One way or another, everyone agrees on the infinity of the Universe, but interprets this infinity in completely different ways. Some consider the Universe to be multidimensional, where our “local” three-dimensional Universe is only one of its layers. Others say that the Universe is fractal - which means that our local Universe may be a particle of another. We should not forget about the various models of the Multiverse with its closed, open, parallel universes, wormholes. And there are many, many different versions, the number of which is limited only by human imagination.

But if we turn on cold realism or simply step back from all these hypotheses, then we can assume that our Universe is an infinite homogeneous container of all stars and galaxies. Moreover, at any very distant point, be it billions of gigaparsecs from us, all the conditions will be exactly the same. At this point, the particle horizon and the Hubble sphere will be exactly the same, with the same relict radiation at their edge. There will be the same stars and galaxies around. Interestingly, this does not contradict the expansion of the Universe. After all, it is not just the Universe that is expanding, but its space itself. The fact that at the moment of the Big Bang the Universe arose from one point only means that the infinitely small (almost zero) sizes that were then have now turned into unimaginably large ones. In the future, we will use precisely this hypothesis in order to understand the scale of the observable Universe.

Visual representation

Various sources provide all sorts of visual models that allow people to understand the scale of the Universe. However, it is not enough for us to realize how big the cosmos is. It is important to imagine how concepts such as the Hubble horizon and the particle horizon actually appear. To do this, let's imagine our model step by step.

Let's forget that modern science does not know about the “foreign” region of the Universe. Discarding versions of multiverses, the fractal Universe and its other “varieties”, let’s imagine that it is simply infinite. As noted earlier, this does not contradict the expansion of its space. Of course, let's take into account that the Hubble sphere and the particle sphere are respectively 13.75 and 45.7 billion light years.

Scale of the Universe

Press the START button and discover a new, unknown world!
First, let's try to understand how large the Universal scale is. If you have traveled around our planet, you can well imagine how big the Earth is for us. Now imagine our planet as a grain of buckwheat moving in orbit around a watermelon-Sun the size of half a football field. In this case, Neptune's orbit will correspond to the size of a small city, the area will correspond to the Moon, and the area of ​​​​the border of the Sun's influence will correspond to Mars. It turns out that our Solar System is just as more than Earth How much bigger is Mars than buckwheat? But this is just the beginning.

Now let’s imagine that this buckwheat will be our system, the size of which is approximately equal to one parsec. Then the Milky Way will be the size of two football stadiums. However, this will not be enough for us. The Milky Way will also have to be reduced to centimeter size. It will somewhat resemble coffee foam wrapped in a whirlpool in the middle of coffee-black intergalactic space. Twenty centimeters from it will be the same spiral “crumb” - the Andromeda Nebula. Around them there will be a swarm of small galaxies of our Local Cluster. The apparent size of our Universe will be 9.2 kilometers. We have come to an understanding of the Universal dimensions.

Inside the universal bubble

However, it is not enough for us to understand the scale itself. It is important to realize the Universe in dynamics. Let's imagine ourselves as giants for whom the Milky Way has a centimeter diameter. As noted just now, we will find ourselves inside a ball with a radius of 4.57 and a diameter of 9.24 kilometers. Let’s imagine that we are able to float inside this ball, travel, covering entire megaparsecs in a second. What will we see if our Universe is infinite?

Of course, countless galaxies of all kinds will appear before us. Elliptical, spiral, irregular. Some areas will be teeming with them, others will be empty. The main feature will be that visually they will all be motionless while we are motionless. But as soon as we take a step, the galaxies themselves will begin to move. For example, if we are able to discern a microscopic Solar System in the centimeter-long Milky Way, we will be able to observe its development. Moving 600 meters away from our galaxy, we will see the protostar Sun and the protoplanetary disk at the moment of formation. Approaching it, we will see how the Earth appears, life arises and man appears. In the same way, we will see how galaxies change and move as we move away from or approach them.

Consequently, the more distant galaxies we look at, the more ancient they will be for us. So the most distant galaxies will be located further than 1300 meters from us, and at the turn of 1380 meters we will already see relict radiation. True, this distance will be imaginary for us. However, as we get closer to the cosmic microwave background radiation, we will see an interesting picture. Naturally, we will observe how galaxies will form and develop from the initial cloud of hydrogen. When we reach one of these formed galaxies, we will understand that we have covered not 1.375 kilometers at all, but all 4.57.

Zooming out

As a result, we will increase in size even more. Now we can place entire voids and walls in the fist. So we will find ourselves in a rather small bubble from which it is impossible to get out. Not only will the distance to objects at the edge of the bubble increase as they get closer, but the edge itself will shift indefinitely. This is the whole point of the size of the observable Universe.

No matter how big the Universe is, for an observer it will always remain a limited bubble. The observer will always be at the center of this bubble, in fact he is its center. Trying to get to any object at the edge of the bubble, the observer will shift its center. As you approach an object, this object will move further and further from the edge of the bubble and at the same time change. For example, from a shapeless hydrogen cloud it will turn into a full-fledged galaxy or, further, a galactic cluster. In addition, the path to this object will increase as you approach it, since the surrounding space itself will change. Having reached this object, we will only move it from the edge of the bubble to the center. At the edge of the Universe, relict radiation will still flicker.

If we assume that the Universe will continue to expand at an accelerated rate, then being in the center of a bubble and shaking time by billions, trillions and even more high orders years ahead, we will notice an even more interesting picture. Although our bubble will also increase in size, its changing components will move away from us even faster, leaving the edge of this bubble, until each particle of the Universe wanders separately in its lonely bubble without the opportunity to interact with other particles.

So, modern science does not have information about the real size of the Universe and whether it has boundaries. But we know for sure that the observable Universe has a visible and true boundary, called respectively the Hubble radius (13.75 billion light years) and the particle radius (45.7 billion light years). These boundaries depend entirely on the observer's position in space and expand over time. If the Hubble radius expands strictly at the speed of light, then the expansion of the particle horizon is accelerated. The question of whether its acceleration of the particle horizon will continue further and whether it will be replaced by compression remains open.

You probably think that the universe is infinite? May be so. It is unlikely that we will ever know this for sure. It will not be possible to take in our entire universe with a glance. Firstly, this fact follows from the concept of the “big bang”, which states that the universe has its own birthday, so to speak, and, secondly, from the postulate that the speed of light is a fundamental constant. By now, the observable universe, which is 13.8 billion years old, has expanded in all directions to a distance of 46.1 billion light years. The question arises: what was the size of the universe then, 13.8 billion years ago? This question was asked to us by someone Joe Muscarella. Here's what he writes:

“I have seen different answers to the question of what the size of our universe was shortly after the period of cosmic inflation ended. One source says 0.77 centimeters, another says it's the size of a soccer ball, and a third says it's larger than the size of the observable universe. So which one is it? Or maybe something in between?”

Context

The Big Bang and the Black Hole

Die Welt 02/27/2015

How the Universe created man

Nautilus 01/27/2015 By the way, the past year just gives us a reason to talk about Einstein and the essence of space-time, because last year we celebrated the centenary of the general theory of relativity. So let's talk about the universe.

When we observe distant galaxies through a telescope, we can determine some of their parameters, for example the following:

— redshift (i.e. how much the light emitted by them has shifted relative to the inertial frame of reference);

— object brightness (i.e. measure the amount of light emitted by a distant object);

— angular radius of the object.

These parameters are very important, because if the speed of light is known (one of the few parameters that we know), as well as the brightness and size of the observed object (we also know these parameters), then the distance to the object itself can be determined.

In fact, you have to be content with only approximate characteristics of the brightness of the object and its size. If an astronomer observes a supernova explosion in some distant galaxy, then the corresponding parameters of other supernovae located in the neighborhood are used to measure its brightness; we assume that the conditions under which these supernovae erupted are similar, and that there is no interference between the observer and the space object. Astronomers identify the following three types of factors that determine the observation of a star: stellar evolution (the difference between objects depending on their age and distance), an exogenous factor (if the real coordinates of the observed objects differ significantly from the hypothetical ones) and an interference factor (if, for example, the passage of light are influenced by interference, such as dust) - and this is all in addition to other factors unknown to us.

By measuring the brightness (or size) of the observed object, using the brightness/distance ratio, you can determine the distance of the object from the observer. Moreover, from the redshift characteristics of an object, one can determine the extent of the expansion of the universe during the time during which the light from the object reaches the Earth. Using the relationship between matter-energy and space-time, which is explained by Einstein's general theory of relativity, we can consider all possible combinations of different forms of matter and energy that are currently available in the universe.

But that is not all!

If you know what parts the universe consists of, then using extrapolation you can determine its size, as well as find out what happened at any stage of the evolution of the universe, and what the energy density was at that time. As you know, the universe consists of the following components:

— 0.01% — radiation (photons);

- 0.1% - neutrinos (heavier than photons, but a million times lighter than electrons);

- 4.9% - ordinary matter, including planets, stars, galaxies, gas, dust, plasma and black holes;

- 27% - dark matter, i.e. its type that participates in gravitational interaction, but differs from all particles of the Standard Model;

— 68% — dark energy, which causes the expansion of the universe.

As you can see, dark energy is an important thing; it was discovered quite recently. For the first nine billion years of its history, the universe consisted primarily of matter (a combination of ordinary matter and dark matter). However, for the first few millennia, radiation (in the form of photons and neutrinos) was an even more important building block than matter!

Note that each of these components of the universe (i.e. radiation, matter and dark energy) has a different effect on the rate of its expansion. Even if we know that the universe is 46.1 billion light years in extent, we must know the exact combination of its constituent elements at each stage of its evolution in order to calculate the size of the universe at any point in time in the past.

- when the universe was about three years old, the diameter of the Milky Way was one hundred thousand light years;

- when the universe was one year old, it was much hotter and denser than it is now; the average temperature exceeded two million degrees Kelvin;

- one second after its birth, the universe was too hot for stable nuclei to form in it; at that moment, protons and neutrons were floating in a sea of ​​hot plasma. In addition, at that time the radius of the universe (if we take the Sun as the center of the circle) was such that only seven of all the currently existing star systems closest to us could fit into the described circle, the most distant of which would be Ross 154 (Ross 154 - a star in the constellation Sagittarius, distance 9.69 light years from the Sun - approx.);

- when the age of the universe was only one trillionth of a second, its radius did not exceed the distance from the Earth to the Sun; in that era, the expansion rate of the universe was 1029 times greater than it is now.

If you wish, you can see what happened at the final stage of inflation, i.e. just before the Big Bang. To describe the state of the universe at the earliest stage of its birth, one could use the singularity hypothesis, but thanks to the inflation hypothesis, the need for a singularity disappears completely. Instead of a singularity, we are talking about a very rapid expansion of the universe (i.e., inflation) occurring for some time before the hot, dense expansion that gave rise to the current universe. Now let's move on to final stage inflation of the universe (time interval between 10 minus 30 - 10 minus 35 seconds). Let's look at what the size of the universe was when inflation stopped and the big bang happened.

Here we are talking about the observable part of the universe. Its true size is certainly much larger, but we don't know how much. To the best approximation (based on the data contained in the Sloan Digital Sky Survey (SDSS) and information obtained from the Planck space observatory), if the universe bends and folds, then the observable part of it is so indistinguishable from the “unwarped” one that the entire its radius should be at least, 250 times the radius of the observed part.

In truth, the universe may even be infinite in extent, since how it behaved during the early stages of inflation is unknown to us except for the last fraction of a second. But if we talk about what happened during inflation in the observable part of the universe at the very last moment (between 10 minus 30 and 10 minus 35 seconds) before the Big Bang, then we know the size of the universe: it varies between 17 centimeters (at 10 at minus 35 seconds) and 168 meters (at 10 at minus 30 seconds).

What is seventeen centimeters? That's almost the diameter of a soccer ball. So, if you want to know which of the indicated sizes of the universe is closest to the real one, then stick to this figure. What if we assume dimensions smaller than a centimeter? This is too little; however, if we take into account the limitations imposed by cosmic microwave radiation, it turns out that the expansion of the universe could not have ended at such high level energies, and therefore the above-mentioned size of the universe at the very beginning of the “Big Bang” (i.e., a size not exceeding a centimeter) is excluded. If the size of the universe exceeded the current one, then in this case it makes sense to talk about the existence of an unobservable part of it (which is probably correct), but we have no way to measure this part.

So, what was the size of the universe at the time of its origin? If you believe the most authoritative mathematical models describing the stage of inflation, it turns out that the size of the universe at the time of its origin will fluctuate somewhere between the size of a human head and a city block built up with skyscrapers. And there, you see, only some 13.8 billion years will pass - and the universe in which we live appeared.

Each of us has thought at least once about what a huge world we live in. Our planet is an insane number of cities, villages, roads, forests, rivers. Most people don’t even get to see half of it in their lifetime. It is difficult to imagine the enormous scale of the planet, but there is an even harder task. The size of the Universe is something that, perhaps, even the most developed mind cannot imagine. Let's try to figure out what modern science thinks about this.

Basic concept

The Universe is everything that surrounds us, what we know and guess about, what was, is and will be. If we reduce the intensity of romanticism, then this concept defines in science everything that exists physically, taking into account the time aspect and laws governing the functioning, interconnection of all elements, and so on.

Naturally, it is quite difficult to imagine the real size of the Universe. In science, this issue is widely discussed and there is no consensus yet. In their assumptions, astronomers rely on existing theories formation of the world as we know it, as well as data obtained as a result of observation.

Metagalaxy

Various hypotheses define the Universe as a dimensionless or ineffably vast space, most of which we know little about. To bring clarity and the possibility of discussion of the area available for study, the concept of Metagalaxy was introduced. This term refers to the part of the Universe that is observable astronomical methods. Thanks to the improvement of technology and knowledge, it is constantly increasing. The metagalaxy is part of the so-called observable Universe - a space in which matter, during the period of its existence, managed to reach its current position. When it comes to understanding the size of the Universe, most people talk about the Metagalaxy. The current level of technological development makes it possible to observe objects located at a distance of up to 15 billion light years from Earth. Time, as can be seen, plays no less a role in determining this parameter than space.

Age and size

According to some models of the Universe, it never appeared, but exists forever. However, the Big Bang theory that dominates today gives our world a “starting point.” According to astronomers, the age of the Universe is approximately 13.7 billion years. If you go back in time, you can go back to the Big Bang. Regardless of whether the size of the Universe is infinite, the observable part of it has boundaries, since the speed of light is finite. It includes all those locations that can affect an observer on earth since the Big Bang. The size of the observable Universe is increasing due to its constant expansion. According to recent estimates, it occupies a space of 93 billion light years.

A bunch of

Let's see what the Universe is like. The dimensions of outer space, expressed in hard numbers, are, of course, amazing, but difficult to understand. For many, it will be easier to understand the scale of the world around us if they know how many systems like the Solar one fit into it.

Our star and its surrounding planets are only a tiny part of the Milky Way. According to astronomers, the Galaxy contains approximately 100 billion stars. Some of them have already discovered exoplanets. It’s not just the size of the Universe that is striking, but the space occupied by its insignificant part, the Milky Way, inspires respect. It takes light one hundred thousand years to travel through our galaxy!

Local group

Extragalactic astronomy, which began to develop after the discoveries of Edwin Hubble, describes many structures similar to the Milky Way. Its closest neighbors are the Andromeda Nebula and the Large and Small Magellanic Clouds. Together with several other “satellites” they form the local group of galaxies. It is separated from a neighboring similar formation by approximately 3 million light years. It’s even scary to imagine how much time it would take a modern aircraft to cover such a distance!

Observed

All local groups are separated by a wide area. The metagalaxy includes several billion structures similar to the Milky Way. The size of the Universe is truly amazing. It takes 2 million years for a light beam to travel the distance from the Milky Way to the Andromeda Nebula.

The further a piece of space is located from us, the less we know about its current state. Because the speed of light is finite, scientists can only obtain information about the past of such objects. For the same reasons, as already mentioned, the area of ​​the Universe accessible to astronomical research is limited.

Other worlds

However, this is not all the amazing information that characterizes the Universe. The dimensions of outer space, apparently, significantly exceed the Metagalaxy and the observable part. The theory of inflation introduces such a concept as the Multiverse. It consists of many worlds, probably formed simultaneously, not intersecting with each other and developing independently. The current level of technological development does not give hope for knowledge of such neighboring Universes. One of the reasons is the same finiteness of the speed of light.

Rapid advances in space science are changing our understanding of how big the Universe is. Current state Astronomy, its constituent theories and the calculations of scientists are difficult for the uninitiated to understand. However, even a superficial study of the issue shows how huge the world is, of which we are a part, and how little we still know about it.

Usually, when they talk about the size of the Universe, they mean local fragment of the Universe (Universe), which is available to our observation.

This is the so-called observable Universe - the region of space visible to us from Earth.

And since the Universe is about 13,800,000,000 years old, no matter which direction we look, we see light that took 13.8 billion years to reach us.

So, based on this, it is logical to think that the observable Universe should be 13.8 x 2 = 27,600,000,000 light years across.

But that's not true! Because over time, space expands. And those distant objects that emitted light 13.8 billion years ago have flown even further during this time. Today they are already more than 46.5 billion light years away from us. Doubling this gives us 93 billion light years.

Thus, the real diameter of the observable universe is 93 billion light years. years.

A visual (in the form of a sphere) representation of the three-dimensional structure of the observable Universe, visible from our position (the center of the circle).

White lines the boundaries of the observable Universe are indicated.
Specks of light- These are clusters of clusters of galaxies - superclusters - the largest known structures in space.
Scale bar: one division above is 1 billion light years, below - 1 billion parsecs.
Our house (in the center) here designated as the Virgo Supercluster, it is a system that includes tens of thousands of galaxies, including our own, the Milky Way.

A more visual idea of ​​the scale of the observable Universe is given by the following image:

Map of the location of the Earth in the observable Universe - a series of eight maps

from left to right top row: Earth - solar system– Nearest stars – Milky Way Galaxy, bottom row: Local Group of Galaxies – Virgo Cluster – Local Supercluster – Observable Universe.

In order to better feel and realize what colossal scales, incomparable with our earthly ideas, we're talking about, worth a look enlarged image of this diagram V media viewer .

What can you say about the entire Universe? The size of the entire Universe (Universe, Metaverse), presumably, is much larger!

But what this entire Universe is like and how it is structured remains a mystery to us...

What about the center of the universe? The observable Universe has a center - it is us! We are at the center of the observable Universe because the observable Universe is simply a region of space visible to us from Earth.

And just as from a high tower we see a circular area with the center at the tower itself, we also see a region of space with the center away from the observer. In fact, more precisely, each of us is the center of our own observable universe.

But this does not mean that we are in the center of the entire Universe, just as the tower is by no means the center of the world, but only the center of that piece of the world that can be seen from it - to the horizon.

It's the same with the observable Universe.

When we look into the sky, we see light that has traveled 13.8 billion years to us from places that are already 46.5 billion light years away.

We do not see what is beyond this horizon.

The website portal is an information resource where you can get many useful and interesting knowledge related to Space. First of all, we will talk about our and other Universes, about celestial bodies, black holes and phenomena in the depths of outer space.

The totality of everything that exists, matter, individual particles and the space between these particles is called the Universe. According to scientists and astrologers, the age of the Universe is approximately 14 billion years. The size of the visible part of the Universe occupies about 14 billion light years. And some claim that the Universe extends over 90 billion light years. For greater convenience, it is customary to use the parsec value in calculating such distances. One parsec is equal to 3.2616 light years, that is, a parsec is the distance over which the average radius of the Earth's orbit is viewed at an angle of one arcsecond.

Armed with these indicators, you can calculate the cosmic distance from one object to another. For example, the distance from our planet to the Moon is 300,000 km, or 1 light second. Consequently, this distance to the Sun increases to 8.31 light minutes.

Throughout history, people have tried to solve mysteries related to Space and the Universe. In the articles on the portal site you can learn not only about the Universe, but also about modern scientific approaches to its study. All material is based on the most advanced theories and facts.

It should be noted that the Universe includes big number known to people various objects. The most widely known among them are planets, stars, satellites, black holes, asteroids and comets. At the moment, most of all is understood about the planets, since we live on one of them. Some planets have their own satellites. So, the Earth has its own satellite - the Moon. Besides our planet, there are 8 more that revolve around the Sun.

There are many stars in Space, but each of them is different from each other. They have different temperatures, sizes and brightness. Since all stars are different, they are classified as follows:

White dwarfs;

Giants;

Supergiants;

Neutron stars;

Quasars;

Pulsars.

The densest substance we know is lead. In some planets, the density of their substance can be thousands of times higher than the density of lead, which raises many questions for scientists.

All planets revolve around the Sun, but it also does not stand still. Stars can gather into clusters, which, in turn, also revolve around a center still unknown to us. These clusters are called galaxies. Our galaxy is called Milky Way. All studies conducted so far indicate that most of the matter that galaxies create is so far invisible to humans. Because of this, it was called dark matter.

The centers of galaxies are considered the most interesting. Some astronomers believe that the possible center of the galaxy is a black hole. This unique phenomenon, formed as a result of the evolution of a star. But for now, these are all just theories. Conducting experiments or studying such phenomena is not yet possible.

In addition to galaxies, the Universe contains nebulae (interstellar clouds consisting of gas, dust and plasma), cosmic microwave background radiation that permeates the entire space of the Universe, and many other little-known and even completely unknown objects.

Circulation of the ether of the Universe

Symmetry and balance of material phenomena is the main principle structural organization and interactions in nature. Moreover, in all forms: stellar plasma and matter, world and released ethers. The whole essence of such phenomena lies in their interactions and transformations, most of which are represented by the invisible ether. It is also called relict radiation. This is microwave cosmic background radiation with a temperature of 2.7 K. There is an opinion that it is this vibrating ether that is the fundamental basis for everything filling the Universe. The anisotropy of the distribution of ether is associated with the directions and intensity of its movement in different areas of invisible and visible space. The whole difficulty of studying and research is quite comparable with the difficulties of studying turbulent processes in gases, plasmas and liquids of matter.

Why do many scientists believe that the Universe is multidimensional?

After conducting experiments in laboratories and in Space itself, data was obtained from which it can be assumed that we live in a Universe in which the location of any object can be characterized by time and three spatial coordinates. Because of this, the assumption arises that the Universe is four-dimensional. However, some scientists, developing theories of elementary particles and quantum gravity, may come to the conclusion that the existence large quantity measurements are simply necessary. Some models of the Universe do not exclude as many as 11 dimensions.

It should be taken into account that the existence of a multidimensional Universe is possible with high-energy phenomena - black holes, the big bang, bursters. At least, this is one of the ideas of leading cosmologists.

The expanding Universe model is based on the general theory of relativity. It was proposed to adequately explain the redshift structure. The expansion began at the same time as the Big Bang. Its condition is illustrated by the surface of an inflated rubber ball, on which dots - extragalactic objects - were applied. When such a ball is inflated, all its points move away from each other, regardless of position. According to the theory, the Universe can either expand indefinitely or contract.

Baryonic asymmetry of the Universe

The significant increase in the number of elementary particles over the entire number of antiparticles observed in the Universe is called baryon asymmetry. Baryons include neutrons, protons and some other short-lived elementary particles. This disproportion occurred during the era of annihilation, namely three seconds after the Big Bang. Up to this point, the number of baryons and antibaryons corresponded to each other. During the mass annihilation of elementary antiparticles and particles, most of them combined into pairs and disappeared, thereby generating electromagnetic radiation.

Age of the Universe on the portal website

Modern scientists believe that our Universe is approximately 16 billion years old. According to estimates, the minimum age may be 12-15 billion years. The minimum is repelled by the oldest stars in our Galaxy. Its real age can only be determined using Hubble's law, but real does not mean accurate.

Visibility horizon

A sphere with a radius equal to the distance that light travels during the entire existence of the Universe is called its visibility horizon. The existence of a horizon is directly proportional to the expansion and contraction of the Universe. According to Friedman's cosmological model, the Universe began to expand from a singular distance approximately 15-20 billion years ago. During all the time, light travels a residual distance in the expanding Universe, namely 109 light years. Because of this, each observer at moment t0 after the start of the expansion process can observe only a small part, limited by a sphere, which at that moment has radius I. Those bodies and objects that are at this moment beyond this boundary are, in principle, not observable. The light reflected from them simply does not have time to reach the observer. This is not possible even if the light came out when the expansion process began.

Due to absorption and scattering in the early Universe, given the high density, photons could not propagate in a free direction. Therefore, an observer is able to detect only that radiation that appeared in the era of the Universe transparent to radiation. This epoch is determined by the time t»300,000 years, the density of the substance r»10-20 g/cm3 and the moment of hydrogen recombination. From all of the above it follows that the closer the source is in the galaxy, the greater the redshift value for it will be.

Big Bang

The moment the Universe began is called the Big Bang. This concept is based on the fact that initially there was a point (singularity point) in which all energy and all matter were present. The basis of the characteristic is considered to be the high density of matter. What happened before this singularity is unknown.

There is no exact information regarding the events and conditions that occurred at the time of 5*10-44 seconds (the moment of the end of the 1st time quantum). In physical terms of that era, one can only assume that then the temperature was approximately 1.3 * 1032 degrees with a matter density of approximately 1096 kg/m 3. These values ​​are the limits for the application of existing ideas. They appear due to the relationship between the gravitational constant, the speed of light, the Boltzmann and Planck constants and are called “Planck constants”.

Those events that are associated with 5*10-44 to 10-36 seconds reflect the model of the “inflationary Universe”. The moment of 10-36 seconds is referred to as the “hot Universe” model.

In the period from 1-3 to 100-120 seconds, helium nuclei and a small number of nuclei of the remaining lungs were formed chemical elements. From this moment on, a ratio began to be established in the gas: hydrogen 78%, helium 22%. Before one million years, the temperature in the Universe began to drop to 3000-45000 K, and the era of recombination began. Previously free electrons began to combine with light protons and atomic nuclei. Atoms of helium, hydrogen and a small number of lithium atoms began to appear. The substance became transparent, and the radiation, which is still observed today, was disconnected from it.

The next billion years of the existence of the Universe was marked by a decrease in temperature from 3000-45000 K to 300 K. Scientists called this period for the Universe the “Dark Age” due to the fact that no sources of electromagnetic radiation had yet appeared. During the same period, the heterogeneity of the mixture of initial gases became denser due to the influence of gravitational forces. Having simulated these processes on a computer, astronomers saw that this irreversibly led to the appearance of giant stars that exceeded the mass of the Sun by millions of times. Due to such a large mass, these stars became incredibly hot high temperatures and evolved over a period of tens of millions of years, after which they exploded as supernovae. Heating to high temperatures, the surfaces of such stars created strong streams of ultraviolet radiation. Thus, a period of reionization began. The plasma that was formed as a result of such phenomena began to strongly scatter electromagnetic radiation in its spectral short-wave ranges. In a sense, the Universe began to plunge into a thick fog.

These huge stars became the first sources in the Universe of chemical elements that are much heavier than lithium. Began to form space objects 2nd generation, which contained the nuclei of these atoms. These stars began to be created from mixtures of heavy atoms. A repeated type of recombination of most of the atoms of the intergalactic and interstellar gases occurred, which, in turn, led to a new transparency of space for electromagnetic radiation. The Universe has become exactly what we can observe now.

Observable structure of the Universe on the website portal

The observed part is spatially inhomogeneous. Most galaxy clusters and individual galaxies form its cellular or honeycomb structure. They construct cell walls that are a couple of megaparsecs thick. These cells are called "voids". They are characterized large size, tens of megaparsecs, and at the same time there is no substance with electromagnetic radiation in them. The void accounts for about 50% of the total volume of the Universe.